In recent years, a multiplicity of semiconductor chips are being stacked in one package and the encapsulated stacked multi-chip package has been put into practice to achieve miniaturization and high density implementation of semiconductor devices. The stacked semiconductor device, such as a stacked multi-chip package, is configured by stacking a multiplicity of semiconductor chips on a circuit substrate such as the wiring board or a lead frame in sequence. The semiconductor chip is commonly stacked by using an adhesive layer located on the non-circuit side (back side) which is the opposite side of the circuit side (surface) of the semiconductor chip.
In this case, since a surface protection film on the circuit side of the semiconductor chip, and an adhesive layer on the non-circuit side of the semiconductor chip, are required, it is inevitable that the stacked multiplicity of semiconductor chips, surface protection films and adhesive layers will combine to result in a thicker stack. As a countermeasure to this issue, there are proposals for formation of a surface protection film and adhesive layer combining the function of the surface protection film and adhesive layer and stacking the semiconductor chips by using this surface protection film and adhesive layer. Where the surface protection film and adhesive layer are formed as a single layer, the process of creating the protective film and adhesive film can be done in a single step, which contributes to the reduction of stacked semiconductor device thickness and the fabrication cost. However, the combined surface protecting and adhesive layers have resulted in fabrication issues when stacking two of more chips in a package.
In the case of using the surface protection film and adhesive layer, for example, after forming the surface protection film and adhesive layer on the surface of the semiconductor wafer, the semiconductor chip, having the surface protection film and adhesive layer formed thereon is cut from the semiconductor wafer. As the common package stacking process is employed in the process of stacking the semiconductor chips by picking up and stacking the semiconductor chips in a sequence, which ensures reliability of the adhesion between the semiconductor chips but also prevents separation of the semiconductor chips from the suction collet when picking up the semiconductor chips. Thus, attempts at using a combined surface protection and adhesive material have not met with success.